The present invention relates to the cleaning of the developed photopolymer layer from a photopolymer printing plate.
Photoinitiated polymerized plates are used in the printing industry. It is conventional to dispose of such plates subsequent to printing because there is no known technique for readily removing the polymer without harming the underlying substrate of the plate. This is wasteful as the plates, typically formed of aluminum, could be reused if an effective technique were developed for cleaning.
Various techniques have been employed for removing coating compositions from lithographic plates. U.S. Pat. No. 3,250,644 discloses the use of an acetone and hydrofluoric acid solution for this purpose. This is costly and requires the disposal of the acidic organic solvent which is potentially harmful to the environment. Other techniques for cleaning polymeric substrates have all required the use of organic solvents. See, U.S. Pat. Nos. 3,625,763, 3,784,477, 3,796,602, and 3,998,654.